Civil Engineering Reference
In-Depth Information
Pole sweep: Sweep is the deviation of a pole from straightness. Sweep
will be allowed in one plane and one direction only. A straight line
joining the edges of the structure at both the top and the butt should
not be distant from the pole surface at any point more than 3/8 in.
for each 10 ft of length between these two points.
Weight:
10% of computed value.
Location of longitudinal reinforcement at stressing header:
±
±
1/4 in. for
individual strands,
±
1/8 in. for the centroid of a group of strands.
Spiral reinforcement:
±
25% spacing variance, with total quantity per ft
maintained.
Location of a group of bolt holes from pole tip:
2 in.
Location of centerline between groups of bolt holes:
±
±
1 in.
Location of bolt holes within a group of bolts:
±
1/8 in.
Bolt hole diameter:
+
1/8 in. of specifi ed hole diameter or
+
1/4 in.
greater than actual bolt diameter.
Bolt hole alignment within a group of bolts: within 1/2 of the hole
diameter from the bolt plane that is longitudinal to the pole's cross-
sectional centerline in a group.
Sealing Strand Ends
The ends of strands must be properly sealed against water intrusion.
It has been demonstrated that the helical prestressed strand reinforcement
can act as capillary tubes and draw water up into the member. Hence, it
is extremely advantageous to burn back the strand into the member
approximately 1 in. and then seal the area with an epoxy grout or similar
impervious material. This is especially desirable when pole installations
are in areas with high water tables or for those placed directly in sea water.
Wherever strands are terminated in a pole, care should be taken to ensure
that the strands are protected against weathering and corrosion. Strands
that are attached to bolted fl ange ends should be similarly sealed.
Concrete Mix
Concrete mixes for prestressed concrete should be established by
methods in accordance with ACI 318 (ACI 2008), Chapter 4. Mixes may
be designed either by a commercial laboratory or by qualifi ed plant per-
sonnel. All mix designs should be developed using the specifi ed propor-
tions and type of water, cement, aggregates, and admixtures proposed for
use in plant mixes. Each mix design needs to be validated by adequate
test data. If any of the variables are changed, the mix should be reevalu-
ated. Unless specifi ed, the producer shall have the choice of the type of
cement to use for achieving the specifi ed physical properties. Acceptance
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